Urinary incontinence is an unfortunately common medical complaint. Many treatments have been suggested. Recently, a relatively minimally invasive technique has become more common, in which a bladder neck and/or urethra is supported by a sling, so that the urethra is partially compressed and/or has a support below it so that during straining and/or bladder/uretheral descent, pressure is applied between the urethra and the sling, thereby closing its lumen.
Benderev et. al, in U.S. Pat. No. 5,836,314 and Brenneman et al in PCT publication WO 98/19606, the disclosures of which are incorporated herein by reference, describe exemplary procedures for treating incontinence. Two or more bone anchors are attached to the pubic bone. Each anchor is pre-threaded with a suture. Brenneman suggests attaching a sling to the sutures such that when the sutures are pulled tight and knotted, the sling is urged towards the pubic bone. Benderev suggests integrally molding one end of a suture with a “suture support”, which suture support is provided to prevent damage to the urethra by the sutures.
It should be noted that, prior to the introduction of slings, some earlier procedures, for example the Burch procedure and the M.M.K. procedure, used only sutures without a sling to support the bladder neck. Also the, different, needle bladder neck suspension procedure uses only sutures. The disadvantage of these procedures is that the bare sutures can cut into and damage the urethra. In a sling procedure, described below, a mesh or a wide strip of material contacts the urethra instead of sutures, so that the urethra is not damaged.
FIG. 1 is a schematic side cut-through illustration of a pubic region 20 during such a procedure, before the sutures are tightened. In the figure, a sling 32 is located between a vagina 22 and a bladder neck 26 of a bladder 24. The sling is threaded by a plurality of sutures 36, which are attached to a bone anchor 30, in a pubic bone 28.
There are two commonly applied methods of bringing sling 32 to a position between vagina 22 and bladder neck 26. In a first method, an incision is made in the vagina, at an area corresponding to that marked with reference number 34, perpendicular to the figure plane, thereby forming a flap. The sling is inserted into the incision, under the flap, and after the sling is tightened, the incision is closed. In a second method, only a small hole in the vagina lining is made for each inserted bone anchor and a tunnel is formed between the two holes, for insertion of sling 32 therethrough.
This family of suture-sling techniques has several disadvantages:
(a) the suture is an additional element which may be damaged during the procedure or after it;
(b) knotting the sutures (after they are tightened) takes skill and time; additionally, some patients have complained that the sutures cause discomfort during sexual activity, since such sutures typically have sharp edges and are often bulky as the suture may have to be knotted as many as six times to assure patency;
(c) the sutures add some unwanted leeway between the positioning of the anchors and the positioning of the ends of the sling; and
(d) the sutures may damage the sling by cutting through it (older tissue being more susceptible); if the suture enters the sling at multiple points (to reduce strain at the sling-suture joints) the sling may be deformed by the sutures.
U.S. Pat. No. 3,580,313, to McKnight, the disclosure of which is incorporated herein by reference, suggests using the tissue between the urethra and the vagina as a “sling” and stapling that tissue to the pubic bone. However, this solution may not be suitable for some patients, such as older patients, as their tissue are usually too weak to provide a suitable support. Also, older tissue is more susceptible to cut-through damage from the staples.